ATPase activity in macula densa cells of the rabbit kidney

Na-K- and Mg-activated ATPase activities were determined in maculae densae and glomeruli dissected from both superficial and juxtamedullary nephrons of normal rabbits, using an ultramicro method including a cycling reaction. Activities were expressed as P i generated per macula densa or per glomerulus and normalized for tissue volume. Results indicate that the mean volume of superficial and juxtamedullary macula densa samples was not statistically different, while glomeruli from deep nephrons had sample volumes that were 29% larger than those from superficial nephrons ( P <0.001). Correcting for volume both superficial and juxtamedullary macula densa samples had an Na-K-ATPase activity of 0.37±0.21 fmol · h −1 · (μm 3 ) −1 . Mg-ATPase activity in both pools was also similar [0.41±0.07 and 0.52±0.1 fmol · h −1 · (μm 3 ) −1 ]. Na-K-ATPase activity in macula densa cells is estimated to be about 1/40th the activity of surrounding cortical thick ascending limb cells. Total glomerular ATPase per unit volume was significantly higher in glomeruli from superficial than from deep nephrons [0.41±0.04 vs. 0.28±0.04 fmol · h −1 · (μm 3 ) −1 P <0.05]. There was no statistically significant activity of Na-K-ATPase in either superficial or deep glomeruli. These results suggest that in contrast to previous reports, the macula densa contains Na-K-ATPase, but at a low level relative to surrounding tubular cells. Further, in normal rabbits, this activity is invariant in superficial and juxtamedullary samples.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47454/1/424_2004_Article_BF00580725.pd

Experimental evaluation of rigor mortis. VIII. Estimation of time since death by repeated measurements of the intensity of rigor mortis on rats.

The development of the intensity of rigor mortis was monitored in nine groups of rats. The measurements were initiated after 2, 4, 5, 6, 8, 12, 15, 24, and 48 h post mortem (p.m.) and lasted 5-9 h, which ideally should correspond to the usual procedure after the discovery of a corpse. The experiments were carried out at an ambient temperature of 24 degrees C. Measurements initiated early after death resulted in curves with a rising portion, a plateau, and a descending slope. Delaying the initial measurement translated into shorter rising portions, and curves initiated 8 h p.m. or later are comprised of a plateau and/or a downward slope only. Three different phases were observed suggesting simple rules that can help estimate the time since death: (1) if an increase in intensity was found, the initial measurements were conducted not later than 5 h p.m.; (2) if only a decrease in intensity was observed, the initial measurements were conducted not earlier than 7 h p.m.; and (3) at 24 h p.m., the resolution is complete, and no further changes in intensity should occur. Our results clearly demonstrate that repeated measurements of the intensity of rigor mortis allow a more accurate estimation of the time since death of the experimental animals than the single measurement method used earlier. A critical review of the literature on the estimation of time since death on the basis of objective measurements of the intensity of rigor mortis is also presented

Experimental evaluation of rigor mortis. V. Effect of various temperatures on the evolution of rigor mortis.

Objective measurements were carried out to study the evolution of rigor mortis on rats at various temperatures. Our experiments showed that: (1) at 6 degrees C rigor mortis reaches full development between 48 and 60 hours post mortem, and is resolved at 168 hours post mortem; (2) at 24 degrees C rigor mortis reaches full development at 5 hours post mortem, and is resolved at 16 hours post mortem; (3) at 37 degrees C rigor mortis reaches full development at 3 hours post mortem, and is resolved at 6 hours post mortem; (4) the intensity of rigor mortis grows with increase in temperature (difference between values obtained at 24 degrees C and 37 degrees C); and (5) and 6 degrees C a "cold rigidity" was found, in addition to and independent of rigor mortis

Forensic diaphanoscopy: how to investigate invisible subcutaneous hematomas on living subjects

A significant proportion of subcutaneous hematomas remain undetected after external visual examination of the body. In the case of a cadaver such hematomas can be easily identified through a cutaneous incision but in living persons the diagnosis becomes more complicated. The usual methods, based on diagnostic imaging, do not combine sufficient reliability and feasibility. The results of our investigations demonstrated that forensic diaphanoscopy is a highly sensitive (95%) and specific (97%) means to determine the presence or absence of subcutaneous invisible hematomas. In addition, it is possible to locate such hematomas with great precision, to draw their shape and evaluate their magnitude. The lower limit of detection is of the order of 1 mm. The advantages of this method lie in the fact that it is reliable, non-invasive, has no side effects, is simple to carry out and allows real time scannin

Experimental evaluation of rigor mortis. VII. Effect of ante- and post-mortem electrocution on the evolution of rigor mortis.

The influence of electrocution on the evolution of rigor mortis was studied on rats. Our experiments showed that: (1) Electrocution hastens the onset of rigor mortis. After an electrocution of 90 s, a complete rigor develops already 1 h post-mortem (p.m.) compared to 5 h p.m. for the controls. (2) Electrocution hastens the passing of rigor mortis. After an electrocution of 90 s, the first significant decrease occurs at 3 h p.m. (8 h p.m. in the controls). (3) These modifications in rigor mortis evolution are less pronounced in the limbs not directly touched by the electric current. (4) In case of post-mortem electrocution, the changes are slightly less pronounced, the resistance is higher and the absorbed energy is lower as compared with the ante-mortem electrocution cases. The results are completed by two practical observations on human electrocution cases